Meeting Abstract
Rising ocean temperatures are often implicated in the widespread demise of coral reefs, as high temperatures can lead to a fatal breakdown of the relationship between coral hosts and their single-celled algal symbionts in a process known as coral bleaching. However, recent research has revealed that the effect of warming on corals of the same species may vary widely depending on their thermal history. Specifically, corals from nearshore reef habitats, which experience relatively extreme daily and seasonal seawater temperature fluctuations, have demonstrated higher tolerance to thermal stress than their forereef conspecifics, which experience more thermally stable conditions. Importantly, this intraspecific variation in thermal tolerance has also been shown to be heritable, implying that genetic linkage between resilient nearshore reefs and sensitive forereef populations could foster reef-scale adaptation to ocean warming. Here, we use restriction site-associated DNA sequencing to explore the fine-scale population genomics of the massive starlet coral, Siderastrea siderea, throughout the Belize Barrier Reef System. Tissue micro-samples were collected from 176 colonies of S. siderea across four pairs of nearshore and forereef sites in November 2014 and 2015. These sampling sites were intentionally selected based on their distinct thermal characteristics, where nearshore sites experience both warmer and more variable temperature conditions than those on the forereef. By resolving the patterns of genetic exchange between nearshore and forereef sites on the Belize Barrier Reef, this study provides insight into the prospect of dispersal-driven adaptation, which may be essential to the survival and evolution of Caribbean coral reefs as oceans continue to warm.
